Shiva Purana
अनुग्रहाय लोकानां लिंगानि च महेश्वरः ॥ दधाति विविधान्यत्र तीर्थे चान्यस्थले तथा ॥ १५ ॥
In order to bless the worlds, lord Śiva assumes different phallic forms here in the holy centres as well as in other places.
english translation
anugrahAya lokAnAM liMgAni ca mahezvaraH ॥ dadhAti vividhAnyatra tIrthe cAnyasthale tathA ॥ 15 ॥
hk transliteration by Sanscript